Just a note to let others know if they need a custom lens board for a Beseler, Durst, LPL, Devere, Zone VI enlarger (to mention only a few), I can highly recommend Jose Meneses at Custom Photo Tools in Portugal.
I just received a Beseler 4 x 4 lens board with a 50mm hole and brass retaining ring for my Rodenstock Rodagon 150mm f5.6 enlarging lens. The board is nicely finished with black paint on the front and a velvet-like flocking on the back side. It's hard to find 50mm x 0.75 retaining rings for this lens, but for $38 Euro, I am very pleased with the fit and finish of this board/ring combo.
Jose may be a well known entity on Photrio, but this was my first experience with him and it was extremely positive.